Derek, Rory and Bolivia are reunited over the Christmas school break in this sequel to The Hot and Cold Summer. Bolivia's week-long return to New Jersey is joyously welcomed by her great-aunt and great-uncle, and her two favorite fifth-grade neighbors. The threesome pass their hours together playing games, ice-skating, building snowpeople (and moving them from one house to the other in the dead of night) and solving the mystery of the disappearances of Bolivia's new Swiss army knife, Derek's hamster and the money from his bank. Their friendship is tested by their mistrust of one another, which peaks when Derek's suspicions of Rory's dishonesty threaten to tear the trio apart. There is a logical explanation for everything, luckily, which leaves the door open for another satisfying sequel about these terrific friends. Ages 8-12. (September)